Radial abundance gradients derived using the relation O3N2 from Pettini & Pagel (2004) for two of the galaxies. In each left panel the three redshift regimes are over-plotted, the empty circles correspond to Z0, the blue circles to Z1, and the orange squares to Z2. The three points in the bottom left corner show the average error bars. In the right panels we can see a linear regression fitting to each regime.